22-01-2018, 11:41 AM
The datasheet (link in post #7) shows that a pull-up resistor is included with this one, so there should be a healthy 5V signal.
Aside from physical aspects, these receiver ICs are much of a muchness, so it's worth rescuing them from scrap gear for test purposes. They can be used to make a very simple IR tester for those who like to build their own gear, and are also very useful for projects too. Not that they're expensive to buy, but it's nice to have something in the drawer to quickly test a theory at times like this.
Looking at the service manual of the receiver, I see that there's a surprising amount of circuity between the receiver and the microprocessor. Starting on the front panel (B board), it goes via 2 transistors. It travels from there to the audio input board A and straight through to the video input board N. On there is an IR input jack followed by another transistor. The signal travels through the contacts in that jack, so have they tarnished? There's also an IR output jack, so checking to see if the IR signal is there might save a bit of time... Next, another transistor, then back to the A board, then back to the front panel board, then finally into the microprocessor (IC201) on pin 8. So personally, I'd be chasing that signal with a 'scope, as there's a lot to go wrong besides the receiver.
Aside from physical aspects, these receiver ICs are much of a muchness, so it's worth rescuing them from scrap gear for test purposes. They can be used to make a very simple IR tester for those who like to build their own gear, and are also very useful for projects too. Not that they're expensive to buy, but it's nice to have something in the drawer to quickly test a theory at times like this.
Looking at the service manual of the receiver, I see that there's a surprising amount of circuity between the receiver and the microprocessor. Starting on the front panel (B board), it goes via 2 transistors. It travels from there to the audio input board A and straight through to the video input board N. On there is an IR input jack followed by another transistor. The signal travels through the contacts in that jack, so have they tarnished? There's also an IR output jack, so checking to see if the IR signal is there might save a bit of time... Next, another transistor, then back to the A board, then back to the front panel board, then finally into the microprocessor (IC201) on pin 8. So personally, I'd be chasing that signal with a 'scope, as there's a lot to go wrong besides the receiver.
